1. Field of the Invention
The present invention generally relates to a light guide plate, backlight module and a liquid crystal display, and especially relates to a light guide plate, a backlight module and a liquid crystal display using the same with higher luminance, light outputting efficiency and light concentration.
2. Description of Related Art
A liquid crystal display which can produce colorful image has been applied broadly to notebook computer, personal digital assistant and desktop and replaced traditional cathode ray tube display, because of its lightweight, lower power consumer and low radiation pollution.
FIG. 1 shows a conventional liquid crystal display (LCD). LCD 1 comprises backlight module 2, optical film 20 and liquid crystal display panel 30. Image L can be displayed successfully via the light produced by backlight module 2. Backlight module 2 comprises light guide plate 10, light source 50, cover 60 and reflector 40. Light guide plate 40 has upper surface 12, bottom surface 14 and light input surface 16. Light source 50 for providing light is disposed adjacent to the light input surface 16 of the light guide plate 10. Cover 60 protects light source 50. Light source 50 is a cold cathode fluorescent lamp (CCFL), disposed on the lamp holder (not shown), and lamp wire (not shown) extends from the lamp holder and is electrically connected with a connector. Alternatively, a plurality of light-emitting diodes (LEDs) or external electrode fluorescent lamp (EEFL).
Light guide plate 10 is for changing the path of the light. Light from the light source 50 can reach to the liquid crystal display panel 30 through light guide plate 10. Reflector 40 located under the light guide plate 10 is for reflecting light leaked out of the light guide plate 10, in order to increase reflective efficiency of light.
Optical film 20 above the light guide plate 10 is for further treatment of light, for example, light concentration, diffusion or uniformity. Optical film 20 may be prism lens and/or diffuser. Number of optical film can be one or more. However, because of the optical film 20, it is difficult to control the brightness and uniformity of the light from the backlight module 2.